This invention relates generally to apparatus for neural and muscle stimulation such as for facilitating hearing in the deaf, and more particularly the invention relates to a method and means for stimulating by means of electrical pulses.
The use of subcutaneously implanted hearing devices is known. U.S. Pat. No. 3,209,081 discloses a device which is implanted in the mastoid bone. The receiver makes direct contact with the bone through which sound waves may be conducted to the inner ear.
More recently, implanted prosthetic devices for stimulating the auditory nerve by means of electrical pulses have been disclosed. U.S. Pat. No. 3,449,768 discloses the use of coded pulse trains to create an electrical gradient field to facilitate visual or audio stimulations, U.S. Pat. No. 3,752,939 discloses the use of an electrode including a pair of elongated conductors for implanting in the cochlea.
Schindler et al., "Multielectrode Intracochlear Implants" Arch Otolaryngol, Vol. 103, December 1977, discloses the use of spatial excitation of the cochlear nerve in cats. Clark and Hallworth, "A Multiple-Electrode Array for Cochlear Implant," J. Laryngol, Otol, 90/7, 1976 discloses a ribbon array including a plurality of elongated flat electrodes which are positioned along the length of the cochlea for stimulating the auditory nerve. Similarly, bundles of thin wires have been employed by the Stanford Auditory prosthesis group by direct placement into the auditory nerve.
European patent application No. 78300567.1 by Foster et al. and German Pat. No. 2,823,798 by Hochmair et al. both describe multi-channel implantable hearing aids for the deaf containg active circuits.